runtests: add an IPv6 command line flag
Now we have all IPv6 related issues fixed, add a command line flag so people
could actually run tests with IPv6.
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true